The choice of treatment method for genitourinary malignancies is highly- dependent upon the local extent of the tumors. Aggressive surgical procedures with the potential for morbidity or mortality may be inappropriate if regional lymph node or more distant metastases are present. While current cross-sectional imaging methods such as CT or MRI are very good, they cannot detect small foci of metastatic tumor in lymph nodes with satisfactory sensitivity to avoid surgery. Since we have shown that several genitourinary cancers have increased glucose utilization and accumulate FDG avidly, this proposal evaluates the efficacy of PET scanning with 2-deoxy-2 [18F] fluoro-d-glucose (FDG) for the imaging of regional metastases of several genitourinary malignancies. Four different genitourinary tumors will be evaluated: Patients with newly diagnosed bladder cancer scheduled for radical cystectomy and nodal dissection will undergo FDG PET scans of the regional draining lymph nodes of the bladder preoperatively. Patients with newly diagnosed renal masses believed to represent renal cancer will have PET scans performed preoperatively to assess the local extent of disease. Patients with newly diagnosed prostate cancer scheduled for radical prostatectomy will similarly undergo FDG PET scanning prior to surgical excision of the primary tumor and lymph node sampling. Finally, patients with a history of nonseminomatous testicular cancers who have residual masses post-chemotherapy that are scheduled for resection will undergo FDG PET prior to surgical of the mass. Patients with all four tumor types will also receive an i.v. tracer FDG injection immediately prior to surgery so that the uptake of FDG can be assessed in the biopsy specimens containing tumor-involved and normal tissues.Routine cross-sectional imaging studies and PET scans will be compared to enhance the accuracy of the PET staging procedure. Tumor histology and FDG uptake in the resected tumors will be correlated. These studies should allow us to determine the role of FDG PET in the role of FDG PET scanning in the imaging management of patients with genitourinary malignancies.